1. Field of the Invention
This invention relates to fluid handlin; systems in vehicles and, in particular, to a valve assembly for controlling tile flow of coolant exiting a vehicle engine.
2. Discussion of Related Art
In a conventional vehicle fluid handling system, engine coolant travels between a vehicle engine, a radiator, and a hearer core. In particular, coolant is provided So the engine and heat is transferred from the engine to the coolant. Upon exiting the engine, the coolant flows to one or both of the radiator and the heater core. Heat is then vented into the air by the radiator or into the passenger compartment of the vehicle by the heater core, respectively. Finally, the coolant returns from the radiator and/or heater core to a pump that provides the coolant to the engine again.
The flow of coolant from the engine to the radiator is typically regulated using a thermostat. The thermostat controls the amount of coolant flowing from the engine to the radiator responsive to the temperature of the engine as indicated by the engine coolant. When the engine temperature is relatively low, the thermostat limits or prevents the flow of coolant from the engine to the radiator so that the engine warms up more quickly. In this circumstance, coolant is frequently directed through a bypass directly to the pump and/or engine. When the coolant temperature reaches a predetermined temperature, the thermostat allows coolant to flow to the radiator.
The use of a thermostat in conventional fluid handling systems is disadvantageous. In particular, the physical geometry of conventional thermostats is affected by the temperature of the engine coolant. As a result, conventional thermostats often allow coolant to pass (or leak) from the engine to the radiator before a predetermined temperature is reached at which the thermostat is designed to open the passageway between the engine and radiator. This reduces engine efficiency under certain operating conditions because the engine cannot reach a desired operating temperature as quickly as desired. As a result, fuel economy is reduced and emissions increased relative to desired values.
The inventors herein have recognized a need for a valve assembly for controlling an amount of coolant exiting an engine that will minimize and/or eliminate one or more of the above-identified deficiencies.
The present invention provides a valve assembly for controlling an amount of coolant exiting an engine.
A valve assembly in accordance with the present invention includes a valve housing mounted to the engine and having a passage extending therethrough. The valve housing may be mounted to a variety of engine components including the engine block, the cylinder head, a crossover casting, or the intake manifold. The passage of the valve housing is in fluid communication with a coolant outlet in the engine. The assembly also includes a motor disposed within the valve housing. The motor includes a motor shaft extending therefrom. The assembly also includes a valve shaft configured to rotate responsive to rotation of the motor shaft. The valve shaft maybe driven through one or more gears disposed between the motor and valve shafts. Finally, the assembly includes a plate rotatably supported on the valve shaft within the passage defined in the valve housing. The rotational position of the plate controls the amount of coolant exiting the engine.
A valve assembly in accordance with the present invention has several advantages as compared to conventional devices for controlling coolant exiting an engine. First, engine coolant temperature has less of an effect on the inventive valve assembly than on conventional thermostats. As a result, the inventive valve assembly allows little if any coolant to pass prior to the temperature at which the valve assembly is designed to open. Engine efficiency is therefore increased resulting in greater fuel economy and reduced engine emissions. Second, the inventive assembly tolerates contamination from the engine coolant better than conventional devices and therefore has a greater lifespan and requires less maintenance than conventional devices. Third, the inventive assembly integrates the valving member and the components that drive the valving member in a single assembly that is directly coupled to the engine. In this manner, the inventive assembly improves packaging, requires less material, reduces potential coolant leak points and improves bearing alignment for the valve shaft.